Flattened Giant Millipede Beetle vs Riffle Beetle

Side-by-side species comparison

Attribute Flattened Giant Millipede Beetle Riffle Beetle
Scientific Name Passalus unicornis Elmis aenea
Order Coleoptera Coleoptera
Family Passalidae Elmidae
Size 30-45 mm 1.5-2.5 mm
Habitat Woodlands Rivers & Streams
Diet Wood Feeders Detritivores
Regions Central Africa (Cameroon, Gabon, DRC, Congo) Europe
Conservation Least Concern Least Concern

Flattened Giant Millipede Beetle

A large, flattened bess beetle with a shiny black body and a small horn on the head. Adults and larvae live together in rotting logs in a subsocial arrangement. Adults produce sounds by rubbing their hindwings against the abdomen.

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Did You Know?

Parents feed their larvae pre-chewed wood and communicate with them using stridulatory sounds, one of the few examples of parental care in beetles.

Riffle Beetle

A tiny, dark beetle that spends its entire adult life underwater clinging to rocks in riffles. It breathes using a plastron, a permanent thin film of air.

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Did You Know?

Its plastron air film never needs replenishing, allowing it to remain permanently submerged.